Heat treating drum

ABSTRACT

A drum for the heat treatment of erosive material, including lifting blades replaceably attached to the inside of the drum, and separate wear plates for protecting the internal surface of the drum between the blades.

United States Patent Henning 1 Oct. 7, 1975 [5 1 HEAT TREATING DRUM 2,704,636 3/1955 Weston 241/183 3,042,323 7/1962 Hall 241/183 [75] Invent Kurt Neubeckum 3,191,874 6/1965 Drinkwater et a1 241 183 Germany 3,318,537 5/1967 Wallin et a1. 1 51/164 3,592,454 7/1972 Olsen 432/118 [73] Asslgnee. Polysrus AG, Neubeckum, Germany 3.717.937 2,1973 Thompson." u 34/108 [22] Filed: Nov. 2, 1973 3,807,936 4/1974 Verlng 34/108 3,853,458 12/1974 Wurr et a1. 432/1 18 1 p 412,429 3,869,247 3/1975 Deussner 432/118 FOREIGN PATENTS OR APPLICATIONS [3O] Appl'cat'on Pmmy Data 999,521 7/1965 United Kingdom 241/183 Nov. 10, 1972 Germany 2255069 Primary ExaminerJohn J. Camby [52] U.S. C1; 432/118; 259/81 R; 241/183 Assistant Examiner Henry Yuen [51] II.- Cl. F27B 7/14 Attorney Agent or Firm Learman & c u [58] Fleld of Search 432/103, 106, 108, 118, 432/110; 110/14; 259/3, 81;34/165, 166, 173,137,108, 109,124,125; 165789-91; [57] ,ABSTRACT 24 51/163, 164 A drum for the heat treatment of eroslve matenal, 1ncluding lifting blades replaceably attached to the in- 5 References Cited side of the drum, and separate wear plates for protect- UNn-ED STATES PATENTS lbliidgsle internal surface of the drum between the 1,986,530 1/1935 Read 241/183 2,084,713 6/1937 Thayer 432/103 4 Claims, 3 Drawing Figures III'I'... ,A\ \\t,;-

US. Patent Oct. 7,1975 Sheet 1 of2 3,910,756

Fig. 2

. iii I i 51 7 i i L U.S. Patent 001. 7,1975 Sheet 2 of2 3,910,756

HEAT TREATING DRUM BACKGROUND OF THE INVENTION This invention relates to apparatus for heat treating abrasive material and more particularly to a rotatable drum including material lifting blades removably secured to the inside of the drum.

To heat treat erosive material, a hollow, material receiving drum is rotated and a hot gas stream is passed through the rotating drum to effect an exchange between the gas stream and the material being treated in the drum. In order to achieve maximum possible efficiency, the drum includes lifting blades which raise the material and convey it through the drum, so that a haze of material extends over at least part of the drum crosssection to produce intensive contact of all the particles of material with the treating gas. In treatment of this type, all the components which come into contact with the erosive material are subject to wear, so that these components have to be replaced from time to time.

In order to protect the internal drum wall both from erosion and from overheating by the material, it is known to provide the lifting blades with plate-shaped, blade feet, lying against the internal drum' wall, and of a size such that the blade feet of peripherally adjacent blades are in contact with, and hence shield, the internal drum wall from the material being treated. The parts of the lifting blades which dip into the material are subject to particularly intense wear and will require replacement well before the blade feet require replacement. Since the blade feet are integral with the lifting blades, the known form of lifting blade thus necessarily means that when replacement of the worn lifting blades becomes necessary, a relatively larger part of the lifting blade foot which is scarcely worn, or not at all worn, must also be thrown away or sold as scrap.

The invention is'thus based on the problem of providing a drum of the type initially described which is notable for an economical construction of the lifting blades combined with effective covering of the internal drum w'all.

According to the invention this problem is solved by mounting peripherally adjacent lifting blades on the lining periphery at a distance from each other, and providing separate wear plates which protect the internal drum lining from overheating and wear in the area between said lifting blades. In this manner, the blade feet of each lifting blade can be kept small enough to provide just sufficient size for attaching the lifting blade to the internal wall of the drum. When lifting blades of this type have to be replaced due to erosion, with apparatus provided by the invention, only the actually worn parts need be replaced, while the wear plates, which are less likely to wear as compared with the lifting blades, can continue being used. Due to this feature there is a considerable financial saving over the operating life of a drum constructed in accordance with the invention.

According to a preferred form of the invention, the lifting blade feet can be made substantially planar, or flat, while the wear plates are curved to match the curvature of the internal drum wall. In this way the lifting blades are made largely independent of the drum diameter so that the same lifting blade model can be used for various drum sizes. This provides a considerable simplification and saving of costs in the storage of spare lift- 7 ing blades.

The present invention may more readily be understood by reference to the accompany drawings, in which:

FIG. 1 is a cross-sectional view taken through a drum constructed according to the present invention;

FIG. 2 is an exploded plan view of a lifting blade and an intermediate wear plate to be assembled therewith; and

FIG. 3 is an enlarged cross-sectional view of a lifting blade with its corresponding wear plate, constructed in accordance with a further embodiment of the invention.

Apparatus constructed in accordance with the present invention, includes a drum, generally designated 1, for the heat treatment of erosive material, for example for cooling hot cement clinker (not shown). Separably mounted to the internal drum surface or wall 2 are a plurality of circumferentially spaced, identically shaped, material lifting blades 3, each consisting in general of a radially inwardly projecting, material lifting blade wall 4 and of a transversely extending blade foot 5 affixed to the internal drum wall 2. The material lifting blades 3 which are adjacent each other in a peripheral direction are disposed at a distance from each other.

In the zones between the lifting blades 3, there are provided separate arcuate wear plates 6 protecting the internal drum wall surface 2 from overheating and wear by the abrasive material being treated. In the embodiment illustrated in the drawing the neighbouring or adjacent lifting blades 3 have between them at least one wear plate 6, affixed to the internal drum wall 2, constructed as an intermediate plate or plates extending from the one end of a blade foot 5 to the adjacent end of the blade foot of the next following lifting blade 3. Thus the wear plates 6 protect those areas of the internal drum wall 2, not covered by the lifting blades 3, from the material being treated and in this way they form an overheating and wear shield for the internal drum wall.

As clearly seen from FIG. 1, the lifting blade feet 5 are made substantially flat, while the wear plates 6 are arcuate and match the curvature of the internal drum wall 2. Thus the same type of blade can be used for drums with different internal diameters, since the foot 5 of each lifting blade, which is made exceedingly short in the peripheral direction, is practically independent of diameter. This facilitates the manufacture of the lifting blades since there is no necessity for precisely matching the curvature of the blade feet to the curvature of the internal drum wall and also facilitates the storage of spare lifting blades.

plates 6, especially when the distances between adjacent lifting blades are large.

The lifting blades and the wear plates 6 could be affixed to the internal drum lining 2 only singly, by screws or pins, so that the feet 5 of the blades would then abut against the corresponding ends of the wear plates 6. It

is, however, desirable for the lifting blades 3 and the wear plates 6 to be so related that the blades 3 can be affixed to the internal drum lining 2 by the wear plates 6. In that case the blades 3 could be attached to the internal drum wall by the wear plates 6 in clamp fashion, so that it is then sufficient merely to screw the wear plates 6 to the drum wall (see FIGS. 1 and 2). The clamp-like attachment can be effected in the manner shown from the drawings by a simple overlapping of the co-operating ends of the lifting blades 5 and the wear plates 6. The overlapping parts could, however, equally well have engaging grooves and projections, or a wedge-type structure. The clamp-like attachment of the lifting blades 3 and wear plates 6 can be used for both one-piece and composite wear plates.

By contrast, one could also connect the lifting blade feet to the internal drum lining, and in this way fix the wear plates 6 by the blades 3. In either case the number of fastening elements is found to be no larger than was necessary with the prior construction which included lifting blades with large, plate-shaped feet.

A further embodiment of the invention is shown in FIG. 3 and includes a drum 11 having an internal wall 12, internally covered by a plurality of abutting or adjacent wear plates 16, each integrally formed. The wear plates 16 have, in central regions, recesses 17 for snugly receiving radially extending projections a provided on the blade feet 15 of a plurality of generally radially inwardly extending lifting blades 13. The area of each recess 17 is less than the area of the associated lifting blade foot 15. Each projection 15a is provided with a radially extending passage 18 which lies opposite a corresponding bore 19 in the drum casing 11. These bores 18, 19 can then receive connecting bolts (not shown) whereby the lifting blades 13 are afiixed to the drum wall. At the same time this attachment also fixes the corresponding wear plate 16 to the internal drum wall 12.

It should also be noted that each wear plate 16, which in general is matched to the curvature of the internal drum wall 12, has, in the vicinity of its recess 17, a section 160 with a fiat or planar surface and whose dimensions are at least as great as the area of the abutting portion of the associated blade foot 15. This blade foot 15, which in this embodiment is again made substantially flat, can thus lie with a relatively large area on the wear plate 16 and thus press the latter against the internal drum wall 12.

As may also be seen in FIG. 3, it may be desirable to construct the wear plates 19 with radially projecting ribs 20, 20a on their radially outer sides which faces the internal drum wall 12. The ribs 20a lie in the vicinity of the recess 17 and are disposed directly against the internal drum wall 12, while the ribs 20 which are at the end region, as seen in the peripheral direction, of the wear plate 16 can be somewhat spaced from the internal drum wall 12. This formation of the wear plates 16 permits effective fitting against the internal drum wall 12, especially when subjected to the deformations which can arise due to heat effects. For this reason it will also be desirable to put a small expansion gap 21 between two wear plates 16 adjacent each other in the peripheral direction.

Finally, it may also be advantageous if the lifting blades and the wear plates are made of different materials. In this way, the various parts of the rotary drum will have an optimum useful life as provided by the invention.

It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.

What we claim is:

1. Apparatus for the heat treatment of erosive material comprising a rotary drum having a cylindrical wall and adapted to receive material to be treated; a plurality of wear plates on the inner surface of said wall and extending circumferentially about the wall to provide a liner; means for securing said wear plates to said wall, said wear plates being curved to conform substantially to the curvature of said wall and selected ones of said plates being spaced from one another at circumferentially spaced intervals; a plurality of uniform material lifting blades within said drum spaced circumferentially about said wall according to the spacing between said se ected ones of said wear plates; and mounting means carried by each of said blades for mounting the latter on said wall, each of said mounting means comprising a foot occupying the space between said selected ones of said wear plates and having a planar surface confronting said wall, the wear plates on opposite sides of each space overlying the adjacent edge of the associated foot and clamping the latter against said wall, each of said lifting blades extending radially inwardly of said drum and having a radial length such that material lifted thereby in response to rotation of said drum falls in a haze.

2. Apparatus as set forth in claim 1 wherein a single one of said wear plates is positioned between each adjacent pair of said lifting blades.

3. Apparatus as set forth in claim 1 wherein each of said wear plates comprises a pair of members between adjacent lifting blades.

4. The apparatus set forth in claim 1 wherein said lifting blades and said wear plates are made of different materials. 

1. Apparatus for the heat treatment of erosive material comprising a rotary drum having a cylindrical wall anD adapted to receive material to be treated; a plurality of wear plates on the inner surface of said wall and extending circumferentially about the wall to provide a liner; means for securing said wear plates to said wall, said wear plates being curved to conform substantially to the curvature of said wall and selected ones of said plates being spaced from one another at circumferentially spaced intervals; a plurality of uniform material lifting blades within said drum spaced circumferentially about said wall according to the spacing between said selected ones of said wear plates; and mounting means carried by each of said blades for mounting the latter on said wall, each of said mounting means comprising a foot occupying the space between said selected ones of said wear plates and having a planar surface confronting said wall, the wear plates on opposite sides of each space overlying the adjacent edge of the associated foot and clamping the latter against said wall, each of said lifting blades extending radially inwardly of said drum and having a radial length such that material lifted thereby in response to rotation of said drum falls in a haze.
 2. Apparatus as set forth in claim 1 wherein a single one of said wear plates is positioned between each adjacent pair of said lifting blades.
 3. Apparatus as set forth in claim 1 wherein each of said wear plates comprises a pair of members between adjacent lifting blades.
 4. The apparatus set forth in claim 1 wherein said lifting blades and said wear plates are made of different materials. 